Hi!

Here is my task:

Find output voltage Vo if Vin1=3V, Vin2=-2V, R1=R2=R3=100KΩ, R4=300KΩ, R5=150KΩ, VCC=15V.

Applying KCL at node 2 we get:

$$-Iin2+I5-Icc=0$$

$$-\frac{V3-V2+Vin2}{R3}+\frac{V2-V3}{R5}-\frac{V3-V2+Vcc}{R4}=0$$

$$-\frac{Vin2-V2}{R3}+\frac{V2}{R5}-\frac{Vcc-V2}{R4}=0$$

$$V1=V2=\frac{Vin2/R3+Vcc/R4}{1/R3+1/R5+1/R4}=1.5V$$

But Multisim give me different voltage V2:

As you can see, Multisim measure 3.226V.

Here is OPAMP setup (since it's ideal, I put some huge numbers for A and input resistance, output resistance is 0):

Any idea what's wrong?

Here is my task:

Find output voltage Vo if Vin1=3V, Vin2=-2V, R1=R2=R3=100KΩ, R4=300KΩ, R5=150KΩ, VCC=15V.

Applying KCL at node 2 we get:

$$-Iin2+I5-Icc=0$$

$$-\frac{V3-V2+Vin2}{R3}+\frac{V2-V3}{R5}-\frac{V3-V2+Vcc}{R4}=0$$

$$-\frac{Vin2-V2}{R3}+\frac{V2}{R5}-\frac{Vcc-V2}{R4}=0$$

$$V1=V2=\frac{Vin2/R3+Vcc/R4}{1/R3+1/R5+1/R4}=1.5V$$

But Multisim give me different voltage V2:

As you can see, Multisim measure 3.226V.

Here is OPAMP setup (since it's ideal, I put some huge numbers for A and input resistance, output resistance is 0):

Any idea what's wrong?

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